Re: ORA-12535: TNS:operation timed out errors for over a year now...

On 8 Jul 2006 17:04:49 -0700, "Charles Hooper" <hooperc2000_at_yahoo.com> wrote:

>* There is a VPN connection or some type of WAN link between the server
>and the client. The VPN or WAN link connection go down temporarily,
>and the client tries to connect to the database (or display a report).
>After a 40 second delay, or whatever the timeout is, the client reports
>ORA-12535: TNS:operation timed out.
>
>* Something on the server is preventing the listener from responding.
>It could be another database on the server is having a bad day -
>listener tries to hand off a connection to the database that is having
>a bad day, and never returns from the handoff. If this happens, you
>will likely see many entries in the alert logs for the databases, and
>possibly several trace files.

Sqlnet uses *two* ports, one to get in touch, one for the actual communications.
The second port is determined *randomly*. If that port isn't opened in the firewall (and why should it), you get 12535.
Listeners don't have a 'bad day'.

There are three workarounds

- set up connection manager on the database server
- set up mts on the database server to a fixed port
- set use_shared_sockets = true

--
Sybrand Bakker, Senior Oracle DBA